The 2012 MLB season kicks off for most teams on Thursday. Although most clubs have finalized their 25-man rosters­ — some are still searching for last-minute roster replacements to fill spots vacated due to injury.

Who could be available through the trade market? What teams are looking in earnest for last-minute replacements to round out their rosters? Which teams could be potential buyers and sellers?

Matt Thornton to the Cincinnati Reds

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The Cincinnati Reds have been looking for a closer ever since Ryan Madson went down earlier this spring with a season-ending elbow injury.

How about Matt Thornton?

The hard-throwing southpaw is currently in the mix for the Chicago White Sox closer’s job. There have been several reports this spring mentioning Thornton as a possible bargaining chip for White Sox GM Kenny Williams. It seems Williams will be asking a lot for any players involved in potential trades — a philosophy he followed during the off-season while pursuing trades for Sergio Santos and Carlos Quentin. .

“We looked to see if we could acquire some of the game's most impactful young players," Williams said in a CBSSPORTS.COMarticle. "Our target list was our target list. We set the price high, and we stuck with it."

If the Reds are willing to part with young prospects Thornton could be had.

Freddy Garcia to the St. Louis Cardinals

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The St. Louis Cardinals took a tremendous hit earlier this spring when Chris Carpenter went down with a shoulder injury. It seems Carpenter may miss an indefinite amount of time as a result. The Cards will now have to rely on Adam Wainwright and a group of inconsistent and unproven starters.

Would Freddy Garcia be a good fit for the Cardinals?

The one thing Garcia has been over the past couple of seasons is consistent. This consistency was an asset to the New York Yankees, where he posted a respectable 12-8 record with a 3.62 ERA in 146.2 innings in 2011.

The acquisition of Garcia would inject some much needed stability into the Cardinals' staff.

Roy Oswalt to the Boston Red Sox

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The Roy Oswalt rumor-go-round has been spinning around and around this spring. He has been rumored to be pursued by the likes of the St. Louis Cardinals, Los Angeles Angels and the Texas Rangers. Another team who has been widely speculated to be a potential suitor is the Boston Red Sox.

Will the Red Sox finally pull the trigger an acquire Oswalt?

It was reported by Boston.com that ace Josh Beckett had his thumb examined on Monday and could possibly miss his first start of the season. In addition, Red Sox closer Andrew Bailey is also dealing with a thumb injury and will be out for a significant amount of time. Not to mention John Lackey — who is already out for the year. The Red Sox may be forced to put Daniel Bard back into the bullpen which would ultimately force GM Ben Cherington to acquire another starter.

Mike Pelfrey to the Baltimore Orioles

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The New York Mets are in the midst of a rebuilding period and it seems Mike Pelfrey could be had for the right price. Pelfrey, who posted a 7-13 record with a 4.74 ERA in 2011 could be a low-cost option for a team such as the Baltimore Orioles.

Pelfrey, 28, is due to make $5.7 million this season and could provide the Orioles with some experience in the back end of their rotation. The Orioles will be without Zack Britton for an extended period of time due to reoccurring shoulder inflammation.

The Mets could benefit by this trade as well if they could acquire a mid-to-low-level prospect from the Orioles.

Ramiro Pena to the Philadelphia Phillies

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The Philadelphia Phillies have lost both Ryan Howard and Chase Utley this spring to injuries.

Would Ramiro Pena be a good fit for Philadelphia?

According to George A. King with the NY Post the Phillies have shown interest in acquiring the 25-year-old utilityman from the New York Yankees. Philly signed some infield help last week in the form of Andres Blanco — who opted out of his minor league deal with the Washington Nationals.

Pena has a career .233 BA and hasn't shown much power in his career, but he could provide a cheap alternative for Philadelphia until their injury situation clears.

Carlos Marmol to the Boston Red Sox

With closer Andrew Bailey out with an apparent thumb injury, Marmol could be an intriguing possibility. If was reported on Wednesday on SI.com that Bailey will be out until at least July.

Red Sox manager Bobby Valentine doesn’t seem very hopeful that Bailey will return before the mid-point of the season.

"I don't think it will be before the All-Star break — is what the trainer told me," Red Sox manager Bobby Valentine said to SI.com when asked for a timetable for Bailey's return.

Marmol posted a 2-6 record with a 4.01 ERA with 34 saves in 2011. The real question is whether or not Chicago Cubs GM Jed Hoyer will part ways with Marmol, who currently is slated to be the team's closer in 2012.

Bobby Abreu to the Cleveland Indians

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The Cleveland Indians took a gamble when they resigned the oft-injured Grady Sizemore to one-year $5 million deal last fall. Unfortunately for the Tribe, Sizemore will be out for a significant amount of time with a lower back injury.

This has created quite a conundrum for the Tribe. They seem to be satisfied with Shin-Soo Choo in right field but don’t seem as comfortable with Shelley Duncan and Michael Brantley anchoring the other two outfield positions.

According to several published reports, the Indians were close to obtaining LA Angels outfielder Bobby Abreu last week, but the deal fell apart because both sides could not agree on financial terms. If the they can work it out, Cleveland may have found a solution for their outfield question.

Kevin Gregg to the Kansas City Royals

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One of the most devastating injuries this spring happened to Kansas City Royals closer Joakim Soria. He will miss the entire 2012 season with his second Tommy John surgery on his pitching elbow. The only good news is that the surgery took place earlier this week and was deemed successful. This now leaves the Royals with a gaping hole in the back end of their bullpen.

Could Kevin Gregg be a potential replacement?

According to CBS Sports Danny Knobler, Baltimore Orioles GM Dan Duquette would like to jettison some extra salary. If the Royals are willing to take on $5.8 million this season, Gregg could be a temporary fix.

Gavin Floyd to the Colorado Rockies

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Floyd has been rumored to be targeted by several teams including most recently, the Toronto Blue Jays. The Colorado Rockies traded their former ace Ubaldo Jimenez this past off-season for highly-touted lefty starter Drew Pomeranz. The Rockies lack a quality top-of-the-rotation anchor as Jeremy Guthrie and Juan Nicasio are good complementary pieces but not stars. Floyd may be able to fill the void.

The price tag is $7 million for the 2012 season — an attractive incentive for Rockies GM Dan O'Dowd. The only caveat to this deal could be the willingness for O'Dowd to part with significant prospects — a prerequisite for any deal with White Sox GM Kenny Williams.